High-speed inlet valve for fluid operated mechanism



April 27, 1954 s. H. BODEN ETAL HIGH-SPEED INLET VALVE FOR FLUID OPERATED MECHANISM Filed Sept. 29, 1949 2 Sheets-Sheet 1 INVENTORS SumueJHBoden and Iph O.Boni ne.

ATTORNEY Apri 7, 1954 s. H. BODEN ET AL 2,676,779 HIGHSPEED INLET VALVE FOR FLUID OPERATED MECHANISM Filed Sept. 29. 1949' f 2 Sheets-Sheet 2 Fig.2.

A 4 453 i in 5? [39' WITNESSES: VENTORS 54W l Sum H.Bo den and ATTORNEY Patented Apr. 27, 1954 HIGH-SPEED INLET VALVE FOR FLUID OPERATED MECHANISM Samuel H. Boden, Turtle Creek, and Ralph 0.

Bonine, Pittsburgh, Pa., assignors to Westinghouse Electric Corporatio'ii} East Pittsburgh, Pa., a corporation of Pennsylvania Application September 29, 1949, Serial No. 118,534

7 Claims. (Cl. 2 51-29) This invention relates to circuit breakers and more Par icularly to high-speed circuit breaker operating. mechanisms of the pneumatic type. I

In the high-speed operation of circuit breakers, it is important to provide quick automatic reclosing of the contacts immediately after interrup tion of ashort circuit. Automatic reclosing time can be materially reduced by quickly reversing the opening movement of the breaker mechanism to reclose the breaker immediately after interruptioh of the circuit. This is particularly true if thereclosing movement is initiated before the breaker reaches full open position. In pneumatically operated mechanisms, high-speed reversal of the moving parts of a large circuit breaker requires an inlet valve which is capable of exceedingly high speed operation in order to quickly admit a charge of gas under pressure to the operating mechanism to reverse the movement of ticular in the appended claims. The invention itself, however, both as to structure and operation, together with additional objects and advantages thereof will best be understood from the following detailed description thereof when read in connection with the accompanying drawings.

in said drawings;

Figure 1 is an elevational view partly in section of a circuit breaker operating mechanism embodying the principles of the invention:

;Eigure 2 is an enlarged elevational sectional view of the inlet valve mechanism;

lfigur 3 is a horizontal sectional view taken on line IIIIII of Figure 2, showing the multiple exhaust ports for the inlet valve; and

l 'figures 4 and 5 illustrate a modification of the inlet valve shown in Figure 2, Fig. 5 being a horizontal sectional view taken on line VV of Fig. 4.

the breaker and quickly reclose the contacts. Beferring to Fig. 1 of the drawings, the op- An 'object of the invention is to provide a circrating mechanism includes a main casting ll cuit breaker operating mechanism of th fluid which is formed to provide a main operating pressure-operated type having an improved highcylinder l3 closed at the upper end by an intespeedinlet valve mechanism. gral part of the casting. The lower end of the Another object of the invention is to provide cylin er I3 is closed by m ans of a member 15. a circuit breaker operating mechanism of the A pe t lever 9 s i ta y u t d at a fiuidpressure-operated type having an improved end O t ec I a d consists of a P of inlet v alve capable of high-speed operation for ic D e levers ly 0116 being Shown) rapidly admitting a charge of compressed gas vo l y mounted at One @116 011 a pivot P 2| to said mechanism. {in in the upper end of a pair of parallel links 23 Another object of the invention is to provide a circuit breaker embodying an operating mechanism operable by fluid pressure to close the breaker having an improved high-speed inlet valve for quickly admitting a, charge of gas under pressure to said mechanism to effect quick reversal of the opening movement of the breaker and quick reclosing of the breaker contacts.

Another object of the invention is to provide a. circuit breaker embodying an operating mechanism of the pneumatic typehaving an improved high-speed inlet valve of simple and compact construction. 7

Another object of the invention is to provide a circuit breaker embodying a pneumatic operating mechanism for closing the breaker having an improved high-speedinlet valve provided with means for varying the speed of operation of the valve.

. Another object of the invention is to provide a circuit breaker according to the preceding paragraphs wherein the inlet valve is substantially leakproof. a

I The novel features that are considered characteristic of the invention are set forth in par- (only one being shown). The lower ends of the links 23 are pivotally supported on a pivot pin 25 mounted in cars 21 projecting upwardly from the. main casting H. The free ends of the operating levers I9 are rigidly connected by means of a cross member 29 and between them carry a sliort shaft 3| on which is mounted a latch roller 33 disposed between'the two levers IS.

The circuit breaker, shown schematically at ll, sed toward open circuit position by means of a gaccelerating spring I8 and is connected to the" operating mechanism by means of an operating rod 35 which is, in turn, pivotally connected to the operating lever [9 by means of a pivotpin 31.

7 The breaker is releasably held in the closed position against the bias of the accelerating spring [8 by means of a latch mechanism indicated generally at 38. Th latch mechanism comprises a main latch 39 of the slip-01f type which engages the latch roller 33 to restrain the operating lever I 9 in the closed position. The mainlatch is pivoted on a pivot pin 4| and is held in latching position by an axuiliary latch pivoted on-a pivot pint! andengaging a. notch in the main latch, the pivot pins 4| and 51 being suitably supported on the main casting H. The latches 39 and 55 are biased to latching position by suitabl spring means 40 and 55 respectively, the main latch 39 being biased against a stop to prevent it from being moved beyond latching position.

The auxiliary latch 55 is provided with a projection 55 which extends directly above the upper end of a trip rod 51 of an electromagnetic trip device 59 which, in addition to thetrip rod 5?, comprises a magnet core H, an energizing coil l3 and a movable armature 15.

Energization of the tripdevice 69 in response to overload currents effects upward movement of the armature and the trip rod 61 which movement actuates the auxiliary latch'55' counterclockwise to effect release of the main latch 39. When this occurs, the accelerating spring I8 moves the operating lever I9 counterclockwise forcing the main latch 39 in unlatchingdirection and quickly moves the circuit breaker to the open position.

The breaker is actuated to the closed position by means of compressed gas admitted to the operating cylinder I3 above an operating piston 93 which is secured to a piston'rod 95 having its upper end suitably secured to the breaker operating rod 35.

As the breaker approaches the closed position, the latch roller 33 (Figure l engages and wipes by the beveled portion of the main latch 39 moving the latch in unlatching direction until the breaker is in the fully closed position, whereupon the main latch under the influence of its biasing means resumes its latching position and the auxiliarylatch 55 is moved to its latching position by its biasing means. In the closed position of the breaker, the piston 93 normally occupies a position near thelower end of the cylinder I3 and is moved to the upper end of the cylinder upon opening movement of the breaker.

Compressed gas is admitted to the upper end of the cylinder I3 above the piston 93 from a suitable source (not shown) of compressed gas through an inlet passage 91 controlled by an improved high-speed inlet valve mechanism indi-' cated generally at I03 secured to the side-of the main casting I I.

Referring to Figure 2, the high-speed inlet valve mechanism comprises a valve housing member I05 rigidly secured to the side of the main casting II adjacent the upper end'thereof and has formed therein a passage I01 cooperating with the inlet passage 91 in the casting I I Also formed in the housing member I05 is a cylinder or valve chamber I09 in which is disposed a piston-type, cup-shaped inlet valve III which normally closes a communication H3 communicating a high-pressure inlet chamber II5 with the passage I01. Compressed gas is supplied from a suitable storage tank (not shown) to the inlet chamber I I5 by means of aconduit II1.

The inlet valve III is biased by means of a compression spring II9 to seatedor closed position. The spring H9 is compressed between the inlet valve III and an upper valve housing- I2I secured to the housing I05 and. forming a closure for the upper end of the cylinder I09;

The bottom of the inlet valve III is recessed to receive a valve facing I23 of tough resilient ma-' terial which is seatedon-an-annular valveseat-- 125 having its upper edge rounded substantial- 1y as shown. The valve facing I23 may-be suitably secured in the recessed lower face of the valve III as, for instance, by cementing and is also retained in place by a flanged collar I21 threadedly engaging a projection I29 integral with the valve III and locked in place by suitable means such as a pin or set screw I30. The lower end of the projection I29 cooperates with the upper end of an adjusting screw ISI threadedly mounted in the lower portion of the housing I and locked in adjusted position by means of a lock nut I33. Since the valve facing I23 is resilient the screw i3 i is adjusted to permit a predetermined pressure of the facing I23 on the valve-seat I25 before the projection I29 engages the screw I3! thus limiting the pressure of the valve facing'onthe valve seat. The adjusting screw I3I .adjustably determines the closed position of the valve I II and is adjustable to com pensate for any wear on the valve facing I23.

The inlet valve II I is of the balanced-pressure type and isprovided with a small port I35 communicating the high-pressure chamber II5 with the cylinder E09 above the valve IiI so that the pressure in the cylinder 5% and'the chamber I I5 is normally the same. The valve I II is actuated to the open position by suddenly exhausting the gas pressure from the cylinder I05 'above the valve which permits the high-pressure gas in the chamber H5 below the valve III to snap it to its fully open position at extremely high speed. The pressure above the valve iII is exhausted through a passage I31 extending axially through'the lower portion of the housing I2I and through a plurality of exhaust ports I39 (see also Figure 3) under the control of an auxiliary pistontype valve I4I di'sposed in an auxiliary valve chamber or cylinder I53 formed in the upper valve housing I2I. The upper end of the cylinder I 13 is closed by means of a cap M5 secured -to the housing IZI by four bolts I41 which extend through suitable openings in the housing i2! and-threadedly engage the lower housing I05 thereby'securing the upper housing I2I to the housing I55. Suitable gaskets are provided between the cap M5 and" the housing I2I, between the housing'I2I and the housing I05, and between the latter housing and the main casting II to completely seal these joints.

The valve Mi is provided with a recess in its lower face in which is mounted 'avalve facing I49 similar to the valve facing I23 for the valve III and suitably secured thereon as by cementing and also by a screw I5I. The valve facing I49 is seated against concentric, annular valve seats I53 having the seating portions thereof rounded off substantially as shown.

The valve MI is also of the balanced-pressure type, and high-pressure gas isadmitted to the cylinder I53 above the valve MI to balance the pressure in the passage I31 below the valve Il by means of a passage I55 inthe housing members I05 and IZI. This passage communicates the high-pressure chamber II5 to the cylinder I43-above the valve Mai and terminates in the cylinder-I43 by a'reduced portion I51.'- The rate of flow of compressed gas to the cylinder I03 is controlled 'by an adjustable valvemember I59 threadedly engaging an opening in 'the housing I2I and having a tapered end extending into the junction of the passage I55 and'the reduced terminal portion I51 thereof. The valve member I59 is locked' in its adjusted position by means of a lock nut I6I.

The valveI II is noi'mally'maintained in closed position due to the'area on-top of the valve on I which the gas pressure. acts in-a downward direction, being muchgreater than the area of upward pressure belowthe valve, the latter being defined by the passagev I31. o

The valve I4! is actuated to open the passages I31I 39 by quickly exhausting the pressure from the cylinder I43 above the valve which permits the high pressure in the passage I31 toquickly snap the valve I 4| to its fully open position. The pressure in the cylinder I43 isexhausted through an exhaust passage I63 in the housing I2I under the control of an electromagnetically operated pilot valve indicated generally at I65. The pilot valve I65 comprises a valve member I61 disposed in a chamber I69 formed in a housing I1I secured by means of bolts I13 (only. one being shown) to the housing I2I.. The ,valve member I61 is seated against a valve seat I and, con trols a passage communicating the chamber I69 to an exhaust port I11 formed in the housing I1 I. A plug I19 screwed into the lowerend of. the chamber I69 closes the chamber.

The valve I61 is adapted to be actuated to. the open position by a low-energy electromagnet I8 I. comprising a magnetic yoke I83 rigidly mounted on the housing member I1 I, an energizing winding I85 and an armature, I81 to which the valve I61 is connected by means of a rod I89, the armature being biased upwardly to close the valve by a spring (not shown).

The operation of the 'mechanism shown in Figures 1 and 2 is as follows assuming the breaker to be in the open position with the operating piston 93 occupying a position in the upper end of the cylinder I3. Compressed gasis admittedto the cylinder I3 abovev the piston 93 to'clcse the breaker by energization of the electromagnet IBI. This may be accomplished manually or automatically by means of a suitable control circuit, preferably of the type shown in Patent No. 2,408,199, issued September 24, 1946, to G. M. Cumming andR. C. Cunningham, and assigned to the assignee of the instant, invention. When the electromagnet IBI isenergized, it opens the pilot valve I65 by moving the valve member I61 downwardly thus opening-the. communication ,be-, tween the passage I63 and the exhaustport I11. When this occurs, thev pressure in the cylinder I43; above the valve MI is. quickly exhausted'to at-1 mosphere, and the pressure in the cylinder I03 and the passage I31 snaps the valve I4I up against the cap I45, thus opening the communication between the passage I31 and the several exhaust passages I39. The pressure in the highpressure chamber II5 thereupon snaps the-main valve element I I I upwardly against a tubular extension I9I of the housing I2I. This effects highspeed opening of the large communication 3- which admits a charge of closin gas through the passages I 3191 to the operating cylinder I3 above the operating piston 93 to move ,the piston downwardly and close the breaker in the manner previously described.- The tubular extension I9I serves as a stop for the main inlet valve I II and also serves tto limitthe volume ot gas in; the cylinder I99 which must be exhausted to efi'ect opening of the valve III. 1 a .L x

As the breakernears the closed position,v the electromagnet I8I is automatically: deenergized permitting a spring (not shown) to closethe pilot valve I61 thus sealing oi? the exhaust passage 53-411. High-pressure gas is then admitted through to passage I55I51 to the cylinder I43 above the valve I II which immediately moves the valve to closed position. ,As soonasthevalve- I41 is closed, high-pressure gas, flowing through the passage I35 in the main inlet valve III quickly equalizes the pressure above and below the valve III and permits the spring II9 to quickly close the main inlet valve thus shutting ofi the communication H3.

In quickautomatic reclosing operations of a circuit breaker of the type disclosed herein, the inlet valve electromagnet is usually energized automatically shortly after the trip device functions. The time for reclosing the breaker contacts following energization of the trip coil then depends largely on the speed with which the main inlet valve operates to admit compressed gas to the mechanism to reverse the movement of the mechanism to reclose the contacts. The herein disclosed invention; has materially reduced the time required to automatically reclose the circuit breaker following the initiation of an opening opmi J When the circuit breaker is closed against a fault .it is necessary to quickly dump the closing charge of high pressuregas from the operating cylinder I3 (Fig. 1) in order to permit high-speed reversal of the moving parts and opening of the breaker. This is accomplished by means of a pneumatically operated exhaust valve (not shown) which controls exhaust ports I92 (Fig. 1). Compressed gas is admitted to operate the exhaust valve through a passage I96 controlled by a pilot valve I98 and a pipe (not shown) but which communicates with the exhaust valve. Ihe pilot valve is connected to and operated by the trip rod 61. i

v When the circuit breaker closes in against a fault the trip device 69 is energized to trip the breaker and, at the same time, opens the pilot valve I98 admitting gas under pressure from the cylinder I3 to actuate the exhaust valve (not shown) and open the exhaust ports I92.

The exhaust valve device is fully disclosed in Patent No. 2,403,082, issued July 2, 1946, to Allan W. Hill and James M. Cumming and assigned to the assignee of the present invention. Reference may be had to this patent for a more complete understanding of the exhaust valve device.

Provisionis made for varying the speed of opening of the inlet valve device shown in Figures 1, 2 and 3 so thatthe same valve may be used in certain applications of the breaker when high-speed reclosing operations are not required. This feature includes the multiple exhaust passages I39 (Figure 3). By increasing the number 01 exhaust passages, the rate of dumping of gas pressure from the cylinder I09 and passage is increased thus increasing the speed of opening of the main inlet valve I I I. Also by decreasing the number of exhaust passages the rate of dumping the gas pressure is decreased which results in slower opening of the main inlet valve.

As an example, in Figure 3 there are shown three passages I39 and one passage I39, the latter having a plug I93 thereon to close it off. If all four of the passages I39-I39 were open, the main inlet valve would open at its maximum speed. But, if in a particular situation, it is desired to ,slow down the speed of opening of the main inlet valve I I I, the plug I93 may be inserted to retard the dumping of pressure above the inlet valve -I I I,- thus correspondingly retarding opening ofthe. valve.- Asa further and finer adjustment'of the opening speed of the valve III, the plug I93 may have an axially disposed opening therethrough. By this adjustment, the point during an-opening .strokeat which the inlet'valve I II will function to cause'rever'sal"of the'movement of the breaker to close the contacts may-be precisely determined.

Another important feature-of the invention is the provision of the outerconcentric valve seat I53 for the valve I4I. It is impossibleto-construct a piston-type valve with such-'close'fit that gas pressure will not leak by the pistonandescape to atmosphere. By the "provision -of the outer valve seat I53, 'anypressureleakingpast the valve member MI is effectually trapped-in the annular area-below the valveaiidoutside the outer valve seat I 53-thus makingthe" entire vane device leakpro'of.

According to the modification of the invention shown in Figures 4 and 5; an uppervalve housing 195 ofsomewhat different-arrangement is 5" ed to the lower valve housing I05 whichis-the same as that shown in Figure 1. 'Ihe h0using'I 95is provided with a cylinder portion I91 in whichis disposed a piston-type valve I99 having a valve facing or insert f of resilient materialsecured in'a recess of the-lower surface thereof. The insert 23! is seated-on an annular valve seat- 203 having a rounded seating surface. The'valve seat 203 defines a large exhaust'passage me which communicates with the atmosphere through a passage 20?. The space below the valve i99 outside the annular valve seat 203 ''communicates with the spacein the-cylinder I09 above-the valve I H by means of a plurality ofpassages-2fl9 extending longitudinally through the lower'wall of the housing I95 and through a cylindrical extension 2 l I integral therewith. Also, the bypass passage I through the valve I I [has been eliminated and a passage 21 3 provided by milling out a portion of the-upper edgeof the-housing IDS communicating thepassage I55 with the valve chamber Iiliiabove the valve I I I so that pressure is supplied back of both ofthevalve'elements through the passage I55.

The operation of the deviceshown in Figure"): is the same as that-0f the "devicesho-w n in-Figure 1. When the valve I99-is opened-the gaspressure above the valve I I I-is exhausted through the multiple passages 2il9-and the large -passages 205 and 201 to atmosphere, thus permitting the pressure inthe high-pressure chamber- I I5 to quickly open the main inlet valve I I I.

One advantage of the device-shownin-Fi-gure 4 is the elimination of one of the valve-seats I53 of the Figure 1 device. This permits theme of a smaller insertZIlI, and the single annular valve seat provides for more-evenly seating of the insert on the valve seat. "At the same time,-the single valve seateflectually prevents any gas pressure leaking past the piston valve I99 from escaping to atmosphere.

By removing the bolts I41, the cap I and the upper housing member I2I may be-readily removed and the valve'members I4IandIII are then accessibleand may be easily'removed.

While the invention'has been'disclosed'in accordance with the provisions of patent statutes, it is to be understood that various changes in the structural detailsthereof may be made without departing from some of the"=es'sential'features of the invention.

We claim as our invention:

1. In a fluid pressure operated mechanism, the combination of inlet valve meansfor' controlling the flowoi fluid under pressure comprising a valve housing having anoimally high pressure inlet chamber and an outletcha'mberg a firstvaive chamber and a second valve chamber "in said valve housing, amain inlet'valve disposed in said first valvechamber, an auxiliary valve "element disposed in said second valve chamben'spaced concentric annular valve seats in said second valve chamber cooperating with said auxiliary valve element, by-pass'passages communicating said high-pressure chamberto said valve chambrs'above said main inlet valve and above said auxiliary valve element, a centrally disposed passage communicating said first valve chamber above said main inlet-valve with 'said' second valve chamber below said auxiliary valve and terminating within the inner one ofsaid concentricannular valve seats, a'plurality of exhaust ports communicating said second'valve chamber below saidauxiliary valve element to atmosphera'said exhaust ports terminating in said second valve chamber between said concentric annular valve seats, and an electromagnetically operated pilot valve operable'to quickly dump the fluid pressure from said second valve chamber above said auxiliary valve to atmosphere thereby permitting fluid pressure in said first valve chamber above said main inlet valve to quickly move said'auxiliary valve to open position to thereby dump the fluid pressure from said'first valve chamber above said main inlet valve through said centrally disposed passage and said exhaust ports to atmosphere, and said fluid pressure in said high-pressure chamber then quickly inovingsaid main inlet valve to open position.

2. In a fluid pressure operated mechanism, the combination of inlet valve means for controlling the flow of fluid under pressure comprising a valve housing'having a high-pressure inlet chamber and an outlet chamber, an inlet port communicating'said inlet and outlet chambers, first and second valve chambers in said housing disposed in axial alignment, an inlet valve in-said first valve chamber controlling said inlet port, spring means biasing said inlet valve closed, an auxiliary valve in said second valve chamber, spaced annular valve seats cooperating with said auxiliary valve, by-pass passage means communicating said high-pressure chamber with said valve chambers'above said inlet valve and said auxiliary valve, passage means communicatingsaidfi'rst valve chamber above said inlet valve-and said second valve chamber below said auxiliaryvalvewithin'the inner valve seat, exhaust port means communicating said second chamber belo'wsaidauxiliary valve to atmosphere, and a pilot valve operable to quickly dump the 'fluid pressure above auxiliary valve to atmospherepermitting fluid pressure in said first valve-chamber above said inlet valve to quickly movesa-id auxiliary valve to'open said passage means "and said exhaust'ports to thereby dump the fluid pressure from said first valve chamber above'said'i-nlet valve to atmosphere, the fluid pressure in said high-pressure chamber quickly movings'aid inletvalve to open position.

3. In-a fluid pressure operated mechanism, the combination of an inlet valve device for controlling the'flow of fluid under pressure comprising a valve housing having a high pressure chamber and an outlet chamber, a partition between saidchambers having an inlet port therein, a main cylinder and a second cylinder in said housing, said cylinders being in axial alignment, an inlet valve in'said main cylinder for controlling said'inlet'port;spring means biasing said inlet valve closed, a communication between said main-cylinder andsaid second cylinder, exhaust port means communicating said second cylinder to atmosphere, inner'and outer annular valve seats insaid second cylinder, an auxiliary valve in said second cylinder, said exhaust port means communicating said second cylinder-below said auxiliary valve to atmosphere, by-pass passage means communicating said high-pressure chamber with said main cylinder and said second cylinder above saidinlet valve and above said auxiliary valve, said auxiliary valve cooperating with said inner annular valve seat to sea-l off said communication between said cylinders and said exhaust port means, said auxiliary valve cooperating with said outer annular valve seat to prevent fluid pressure leaking past said auxiliary valve from escaping to atmosphere, and pilot valve means operable to dump the fluid pressure from said second cylinder to permit said auxiliary valve to open said communication between said cylinder and said exhaust port to thereby permit fluid pressure in said high-pressure chamber to open said inlet valve.

4. In a fluid pressure operating mechanism, the combination of inlet valve means for controlling the flow of fluid under pressure comprising a valve housing having a normally high pressure inlet chamber and an outlet chamber, a first valve chamber and a second valve chamber disposed in axial alignment in said valve housing, a main inlet valve disposed in said first valve chamber, a normally closed auxiliary valve element disposed in said second valve chamber, passage means communicating said first valve chamber above said main inlet valve with said second valve chamber below said normally closed auxiliary valve element, exhaust port means communicating said second valve chamber below said normally closed auxiliary valve element to atmosphere, valve seat means in said second valve chamber cooperating with said auxiliary valve element to normally close both said passage means and said exhaust port means, by-pass passage means communicating said high-pressure chamber to said first and second valve chambers above said main inlet valve and above said auxiliary valve element, and an electromagnetically operated pilot valve operable to quickly dump the fluid pressure from said second valve chamber above said auxiliary valve element to atmosphere thereby permitting the fluid pressure in said first valve chamber above said main inlet valve to quickly move said auxiliary valve element to open position to dump the fluid pressure from said first valve chamber above said main inlet valve to atmosphere whereby said fluid pressure in said high-pressure chamber eflects high-speed opening of said main inlet valve to open position.

5. In a fluid pressure operating mechanism, the combination of an inlet valve device for controlling the flow of fluid under pressure comprising a valve housing having an inlet valve chamoer and an auxiliary valve chamber therein, an inlet valve in said inlet valve chamber for controlling the flow of fluid under pressure, a normally closed auxiliary valve in said auxiliary valve chamber, concentric annular valve seats in said auxiliary valve chamber cooperating with said auxiliary valve, means providing balanced pressure on both sides of each of said valves, both. of said valves being operable to open position upon unbalancing oi the pressure on one side thereof, passage means respectively communicating said inlet valve chamber above said inlet valve with said auxiliary valve chamber below said normally closed auxiliary valve and communicating said auxiliary valve chamber below said normally closed auxiliary valve to atmosphere, said auxiliary valve in the closed position cooperating with said concentric valve seats to close off both of said passage means, and pilot valve means operable to dump the fluid pressure from said auxiliary valve chamber above said auxiliary valve to permit said auxiliary valve to open said passage means to dump the fluid pressure from said inlet valvechamber above said inlet valve thereby permitting highspeed opening of said inlet valve.

6. In a fluid pressure operated mechanism, the combination of an inlet valve device for controlling the flow of fluid under pressure comprising a valve housing two axially aligned valve chambers, an inlet valve in one of said chambers operable to control the flow of fluid under pressure, passage means within said housing normally providing balanced pressure on both sides of said inlet valve, said inlet valve being operable to open position upon unbalancing of said pressure, a second valve in the other of said chambers operable to effect unbalancing of the pressure on one side of said inlet valve to effect opening of said inlet valve, inner and outer concentric valve seats cooperating with said second valve, a relatively large passage communicating said valve chambers within said inner concentric valve seat, a plurality of relatively small exhaust ports communicating the space between said concentric valve seats to atmosphere, a passage means within said housing normally providing balanced pressure on both sides of said second valve, said second valve being operable to open said relatively large passage and said exhaust ports upon unbalancing of said pressure on one side of said second valve, and an electromagnetically operated pilot valve operable to effect unbalancing of the pressure on one side of said second valve to effect opening of said relatively large passage and said exhaust ports.

'7. In a fluid pressure operated mechanism, the combination of an inlet valve device for controlling the flow of fluid under pressure comprising a valve housing having two valve chambers disposed in axial alignment, an inlet valve in one of said chambers operable to control the flow of fluid under pressure, passage means disposed in said housing normally providing balanced pressure on both sides of said inlet valve, said inlet valve being moved to open position upon unbalancing of said pressure, a second valve in the other of said chambers operable to effect unbalancing of the pressure on one side of said inlet valve to effect opening of said inlet valve, spaced inner and outer concentric valve seats cooperating with said second valve, a relatively large passage communicating said valve chambers within said inner concentric valve seat, a plurality of relatively small exhaust ports communicating the space between said inner and outer concentric valve seats to atmosphere, said second valve normally closing said relatively large passage and said exhaust ports, passage means normally providing balanced pressure on both sides of said second valve, said second valve being operable upon unbalancing of the pressure on one side thereof, a pilot valve operable to effect unbalancing of the pressure on one side of said second valve to eiTect opening of said second valve to open said relatively large passage and said exhaust ports, and adjusting means for varying the opening speed of said second valve to thereby vary the rate of unbalancing the pressure on said 1 1' one side-of-said-in1ehva1ye and the speed of opening movementof said inlet valve.

References Cited in the fil'e of this-patent UNITED STATES PATENTS Number 12 Name; Date;- Stewart T Aug; 31, 1926 Brisbane; Mar. 3, 1942 R binson- Sept. '7; 1943 Issigqnis Oct. 24,1944 Coggeshall- Aug-.- '7, 1945 Cumming etal. Sept. 2&1, 1946 Easley etal. May 17, 1949 Plank: June ;10,- 1952 

